Combustion-indicator



D. A. McNAUGHTON.

COMBUSTION INDICATOR APPLICATION FILED AUG.IT. 1915.

1 ,3 1 1 ,905. Patented Au -.,5, 1919;

on fil /1 M @maaa ml! COLUMIIIA PLANnnuAPH to. WASHINGTON, D. c.

DON A. MONAUGHTON, F MARYVILLE, TENNESSEE.

COMBUSTION -INDICATOR.

To all whom it may] concern:

Be it known that I, DON A. MCNAUGH- TON, a citizen of the United States,residing at Maryville, in the county of Blount i and State of Tennessee,have invented a new and useful Improvement in Combustion- Indicators, ofwhich the following is a specification, reference being had to theaccompanymg drawing.

My improvement relates particularly to indicators for indicating thedraft relations in steam boiler furnaces and other furnaces presentingsimilar conditions or construction.

The'object of the improvement is to provide a simple and efficientapparatus whereby indications of draft conditions in several portions ofthe furnace may be simultaneously taken in such manner as that they maybe utilized for correction of conditions and the establishment andmaintenance of proper air and fuel ratios tending to afford the bestcombustion conditions.

The result desired is to transmit to the instrument the pressureconditions at the three principal stages of draft resistance found inthe operation of such furnaces,

and to oppose such pressures in pairs againstopposite ends of oilcolumns in ob servation tubes and positlon said columns with referenceto the difference between the pairs of pressures applied thereto, thecolumn moving out of the normal atmospheric position only a distancewhich is proportional to the difference between said two pressures, thisbeing a movement less than would be the case if normal atmosphericpressure bore against one end of the column and a pressure from one ofthe furnace spaces were transmitted against the op osite end of saidcolumn. i ne of these pressure pairs consistsof the pressure existing inthe damper space (the spacein the stack below the damper) and the otherconsists of the pressure in the combustion space (the space above thegrate), and the other pair of pressures consists of the pressure in thecombustion chamber and the pressure in the ash-pit space (the spacebelow the grate). The pairing of these last two pressures is of spefcial importance in' attaining sensitiveness and range, as will behereinafter described. It may be further observed that with thesepressures paired in opposition to each other, as above stated, an'increase or a decrease Specification of Letters Patent.

Patented Augrii, 1919.

Application filed August 17, 1915 Serial No. 46,003.

in pressure need not necessarily be' indicated on the oil colunm, onlychanges in di llerenres insuch pressures being indicated,

and only such indication being desired. 'If the pressures of either pairincrease or decrease proportionally, the position of the correspondingoil column will remain substantially stationary.

Assuming that, in the operation of such a furnace, the thickness of thefuel bod (or the amount of fuel exposed for combustion) with relation tothe volume of air supply is such as to result in economical andeflicientor so-called complete combustion, there will necessarily exist certain'conditions of draft pressures relative to each other at differentpoints within the furnace" and the setting.

If this relationship of amount of air supply to fuel is disturbed, thedraft pressures will re-ar ange their relationship correspondingly andwill seek a new equilibrium. The apparatus herein described utilizes thedifference in pressures between the pressure in the region of thedamper, in the space above the grate surface, and in the spacebeneaththe grates Where the pressure is reduced below atmosphericpressure, and

these three pressures are equalized in two inclined transparentindicating tubes conveniently located, so that any changes occurring inthe relationship of the pressures within the furnace will show in theaction of the liquid in the indicating tubes. The character and meaningof changes in pressure will be determined plained.

Under all ordinary conditions of operation, the pressure in the threefurnace spaces, the damper space, the combustion space, and

the ash-pit space are unequal, and their.

pressures lncrease progressively along the course of travel of the airand the products of combustion, the pressure in the ash-pit be-' ingrelatively low and the pressure in the combustion chamber being higher,and the pressure in the damper space being yet higher. Inother words,these spaces are 111 series relative to the course of gaseous travel,

and the pressure of said series increases )ro ressivel with travel alonsaid course;

The accompanying drawing shows, a steam boiler and furnace with mylmPI'OKOCl indicating mechanism applied thereto, said mechanism beingshown in elevation.

The furnace is of ordinary form. B is as hereinafter ex:

, H and I are {transparent indicating or observation tubes. The tube, H,has a middle inclinedrportion, H and a portion, H rising from the lowerend ofthe portion, H

and a portion, H rising from the opposite end of the portion, The tube,K, has a middle inclined portion, K from the lower end of which rises aportion, K and from the upper end of Which inclined portion rises aportion, The tubes,H and I, each contain a quantity of liquiclusually oilsufiicient to rise into the portions, and K and to suitable points in,the inclined portions, H

a11rd .A conducting tube, ,1, has one end secured to the upper end .oftheportion, H2. ofthe tube, H, in such manner as to permitcommunicationbetweenthe tube, H and the tube I, and to exclude theoutside atmosphere from theobse wati n tube. The other end ofthetube,1,, opens into thespace, D, below the damper, E,,.0f the smoke-stack, S.A similar conducting tube, 2, issimilarly coneat with t en r e d o h ofthe I,- and hasits opposite endeX- tending into the combustion space, C,said end being-, pen. similar conducting tube, V

3, is similarly connected to the upper end of the arm, K3, of the tube,K,, an d has its other end extendinginto the ash-pit space, A, and saidend is open. A similar conductor pipe,v 4, is similarly connected to theupper endof the armpH f, of the tube, H,

its other end tapped. into the conducting tube, 2 through whichcommunication is made with the combustion space C.

Adjacent the inclined portion, K of the indicator or observation tiibe,is indicator or pointer, J, movableupon a support, 5, which isparallelto the tube portion, K

Adjacent the portion, H of the indicatortube, is another indicatoi" orpointe supported in the same manner on a support, 5, which is parallelto said portion of said 7 tube, Thussaid'pointers are movable,inde 55pendently of eachi'othenupon their supports, so that said pointers maybe made to stand opposite different portions of their.

tubes within the range of the supports, 5.

When the tubes, H and K, are opento, the outer atmosphere and they aresecured at their chosen inclination, the liquid is introduced untilequilibrium is established in each tube with the "liquid in the inclinedportion of the tube standing at a chosen point, which is to bedesignated as the zero A is the ash-' or normal atmospheric point forthe liquid inthe inclined portion of that tube. In the drawings, saidpoints are marked, 0.

Direct communication between said ob servation tubes and the outeratmosphere is then cut off and only communication through the'pipes, 1,2, 3, and 4 permitted. Fire is then established in the furnace and, byany desired tests, brought to the highest practicable stateofefficiency, thisresulting in establishing certain relative pressures inthe spaces, A, C, and D; and such pressures will, by coeperating ashereinafter described establish the oil columns at certain points in theinclined portions of the indicator tubes. Such positions of the oilcolumns are then marked by any convenient method or means. The movablepointers, J, already described, serve for this purpose. They are mademovable because different furnaces will bring these oil columns todifferent positions after the instrument has been secured in positionand a connected and the furnace fired to eflicient condition. It is thenassumed that the furnace must be so fired and the drafts so maintainedas to hold the ends of the oilcolumns opposite or .relative to saidpointers. When these'pointers or other marks have been placed, theyremain unchanged unless at some future timeit is deemed desirable toconduct another test firing with a view to correcting the conditionsascertained by the previoustest firing. I

Then, after the placing and ustmen't of the apparatus has been completedasabove described, the apparatus is ready for use from day to daywithout change of the pointers orthe zero or normal marks (which areneverchanged), excepting that fronr time to time additional oil isinserted,.to compensate for evaporation, to keep the oil columns, whenexposed only to atmospheric pressure, to the normal points, as will behereinafter described.

From day to day, while: operating the furnace, the fireman observes theinclined portions of the observation tubes to note the positions of theoil columns relative tothe pointers. Usually he will aim to so regulatehis firingjand the damper adjustment as to. holdthe oil columns at theirpointers ,but

the damper so as to hold the two oilcolumns at approximately equaldistances from and at thev same side of the pointers, For exainple, ifthe rate of combustion is increased or decreased above the test rate ofhe may also conduct the firing and adjust combustion, but under suchconditionsas to maintain efliciency or approXimatelycomplete combustion,the two columns. may stand at. approximately 1 equal distances aboye orbelow the pointers. i l

It s already stated that there is v advantage in applying the ash-pitpressure.

and the combustion space pressure in opposition to each other on one ofthe observation tubes instead of pairing combustion space pressure withoutside atmosphere pressure. This advantage is two-fold. First, ashorter indicator tube (having the same inclination) may be used thanwould be the case if outside atmosphere pressure were applied to one endof the tube; and, second, the sensitiveness of the indicator action isincreased and the range of pressures which the indicator can deal withis increased.

The use of the longer tube may be avoided by opposing the ash-pitpressure and the combustion chamber pressure to each other on theobservation tube, because the difference between these pressures is lessthan the difference between the outside atmospheric pressure and thecombustion space pressure. That greater difference between saidatmospheric pressure and combustion space pressure would cause a travelof the oil column through a greater distance.

The reason why the instrument is made more sensitive by the opposing orpairing of the combustion chamber pressure and the ash-pit pressure onthe same observation tube is apparently negatived by what is stated inthe last paragraph. For, the suggestion naturally presents itself thatsuch an instrument is made more sensitive proportional to the increaseof travel of the indicating medium (the oil). But in my improvedapparatus the oil column is operated upon by two agents each of which isacted upon and responsive to variations in furnace conditions, whereaswhen the outside atmospheric pressure and the combustion space pressureare paired or opposed to each other on the tube, only one of saidpressures, the combustion space pressure is sensitive to and variableunder variations in furnace conditions, the atmospheric pressureremaining constant or undergoing no changes having any relation toconditlon in the furnace.

Furthermore, while the pressure in the furnace space and in the ash-pitspace are both variable under abnormal conditions, they vary oppositely,sometimes from each other and at other times toward each other. Theaction in either case being to increase the movement of the oil columnand to a greater extent than would be the case if the combustion spacepressure alone and atmospheric pressure were acting in opposition toeach other upon the oil column.

Adjacent each tube and at opposite sides of the pointer, J, on said tubeis placed a symbol, the two symbols adjacent one tube being unlike andthe pair of symbols at each side of the tube being reversed withreference to the other pair in relation to the tubes and connections asshown; that is to say, one of said symbols may be a mime. sign, as shownin the drawings, while the other is a plus sign, also as shown in thedrawings, and the minus sign belonging to one tube beingat the right andthe minus sign belonging to the other tube being at the. left of thecorrespomling pointer, J. Either of said symbols may be placed at theside of the adjacent pointer to which the oil column moves when there isan insullieient supply of air in the furnace. The minus sign ispreferably chosen for this purpose.

Conductor pipes, 1, 2, 3, and 4. are preferably so connected to the endsof the observation tubes as to reverse the symbols of one pair relativeto the other pair, as above stated, in order that the two oil columnsmay move in the same direction under the same change of condition in thefurnace.

For the purpose of facilitating temporarily connecting the observationtubes with the atmosphere to permit observing the oil columns relativeto the zero points and to replenish the oil insaid tubes, a removableplug, P, is placed into one of the upright arms of each of said tubes,and a three-way cut-oil valve, V, is placed on each of the conductortubes, 1, 2, and 3. No such valve is needed on the conductor pipe, 4,because communication with the short arm of the observation tube, H,with the atmosphere is had through the valve, V, which is located on theconductor pipe, 2.

I claim as my invention,

1. In an apparatus of the nature described, the combination with afurnace having a damper space, a combustion space and an ash-pit space,of two observation tubes normally cut off from the outer atmosphere andeach containing liquid, conductor tubing connecting one end of one ofsaid tubes with said damper space and conductor tubing connecting oneend of the other of said observation tubes with the ash-pit, andconduetor tubing connecting the other ends of said observation tubeswith the combustion space, substantially as described.

2. In an apparatus of the nature described, the combination with afurnace having a damper space and a combustion space and an ash-pitspace, of two observation tubes normally cut off from the outeratmosphere and each containing liquid, conductor tubing connecting oneend of one of said tubes with said damper space and conductor tubmgconnecting one end of the other of said observation tubes with theash-pit, and conductor tubing connecting the other ends of saidobservation tubes with the combustion space, and means for temporarilyplacing said observation tubes into connection with the outeratmosphere, substantially as described.

In an apparatus of the nature described,

7 &

the combination With a furnace having a ,damper space and a combustionspace and an ash-pit space, of tWo observation tubes normally cut offfrom the outer atmosphere and each containing liquid, conductor pipingconnecting one end of one of said tubes With said damper space andconductor tubing connecting one end of the other of said observationtubes With the ash-pit, and conductor tubing connecting the other endsof said observation tubes With the con1bus\ tion space, and means forindicating the po' sitions of the liquid columns under test fir ingsubstantially as described.

4. In an apparatus of the nature described, the combination With afurnace having a damper space and a combustion space and an aslrpitspace all normally differing in pressure, of two observation tubesnormally cut of? from the outer atmosphere and each containing a liquid,of means connecting one of said tubes with the spaces having the highestand the intermediate pressure, and means for connecting the other ofsaid tubes With the space having the intermediate pressure and thelowest pressure, substantially as described.

In testimony whereof I have signed my name this 6th day of August, inthe year one thousand nine hundred and fifteen.

DON A. MoNAUGl-ITON.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, 1330.

